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#31
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help exhaust glowing
jeffcoslacker wrote:
> Steve Wrote: > >>Kevin Bottorff wrote: >> >> >>>jeffcoslacker > wrote in <snip> >>>>if external air is admitted before sensing? I'm fascinated. >> <snip> >What did you think I meant by multiple sensors? My bad- I missed the "before sensing" clause. Indeed the whole point of multiple O2 sensors is to have at least one of them always able to sense the raw O2 content of the exhaust coming out of the engine before its either corrupted by the reduction catalyst or by air injection. The downstream sensor measures how well everything works as a system, and enables OBD-II level diagnostics. IOW, the upstream sensor controls the fuel trim, the downstream sensor tells if the emission controls are working. But the whole point is that, even today, air injection is still used to make the oxidation catalyst perform better. LESS air is used, and the big belt-driven air pump is indeed almost (if not) extinct. But air injection lives on. But getting back to the ORIGINAL post- I still say that a glowing exhaust is most likely the result of a misfiring cylinder (or several) since that is the process that dumps ready-to-burn air/fuel mix into the exhaust stream. |
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#32
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help exhaust glowing
Steve Wrote: > jeffcoslacker wrote: > > > Steve Wrote: > > > >>Kevin Bottorff wrote: > >> > >> > >>>jeffcoslacker > wrote in > > <snip> > > >>>>if external air is admitted before sensing? I'm fascinated. > >> > <snip> > > >What did you think I meant by multiple sensors? > > > My bad- I missed the "before sensing" clause. Indeed the whole point of > multiple O2 sensors is to have at least one of them always able to > sense > the raw O2 content of the exhaust coming out of the engine before its > either corrupted by the reduction catalyst or by air injection. The > downstream sensor measures how well everything works as a system, and > enables OBD-II level diagnostics. IOW, the upstream sensor controls the > fuel trim, the downstream sensor tells if the emission controls are > working. But the whole point is that, even today, air injection is > still > used to make the oxidation catalyst perform better. LESS air is used, > and the big belt-driven air pump is indeed almost (if not) extinct. But > air injection lives on. > > But getting back to the ORIGINAL post- I still say that a glowing > exhaust is most likely the result of a misfiring cylinder (or several) > since that is the process that dumps ready-to-burn air/fuel mix into > the > exhaust stream. It could be...I just figured that most people would notice something strange and the post would be like "My car has been running like crap and now..." or "I've been getting terrible gas mileage, and now my manifold is glowing..."...but perhaps I assume too much... Anyways, you got me on that secondary injection...wasn't part of my understanding of the system, and I apologize for doubting you. -- jeffcoslacker ------------------------------------------------------------------------ jeffcoslacker's Profile: http://www.automotiveforums.com/vbul...?userid=219638 View this thread: http://www.automotiveforums.com/vbul...d.php?t=616668 http://www.automotiveforums.com |
#33
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help exhaust glowing
silicon212 > wrote in
: > > The Russian cars of the 80s had cats? > > In Canada they did after a certain point. -- TeGGeR® |
#34
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help exhaust glowing
TeGGeR® > wrote:
: > >> The Russian cars of the 80s had cats? > >In Canada they did after a certain point. Until they fell off, anyway. Like everything else on the Lada. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#35
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help exhaust glowing
So very likely the exhaust system or at least the converter(s) are already damaged. Excessive fuel from cyl miss-fire; most likely multiple miss-fire is the likely cause. Rising combustion temps will increase exhaust temp. Excessive exhaust temp that hinders combustion will in most cases lower combustion temp. -- JustSayGo ------------------------------------------------------------------------ JustSayGo's Profile: http://www.automotiveforums.com/vbul...?userid=330014 View this thread: http://www.automotiveforums.com/vbul...d.php?t=616668 http://www.automotiveforums.com |
#36
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help exhaust glowing
"TeGGeR®" wrote:
> > silicon212 > wrote in > : > > > > > The Russian cars of the 80s had cats? > > > > > > In Canada they did after a certain point. > > -- > TeGGeR® My 86 Jeep CJ7 didn't come with a cat, the 87's did though. Maybe that's the cut off year? Mike 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 http://www.imagestation.com/album/pi...?id=2115147590 (More Off Road album links at bottom of the view page) |
#37
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help exhaust glowing
Mike Romain > wrote in
: > "TeGGeR®" wrote: >> >> silicon212 > wrote in >> : >> >> > >> > The Russian cars of the 80s had cats? >> > >> > >> >> In Canada they did after a certain point. >> > > My 86 Jeep CJ7 didn't come with a cat, the 87's did though. > > Maybe that's the cut off year? Could be. Leaded gas was banned in Canada around about 1987. Some cars had cats earlier. The Mazda RX-7 had one for 1981. In that case, it enabled Mazda to get rid of the trouble-prone thermal reactor. -- TeGGeR® |
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